To make a continuous strip of metal from metallic particles, a continuous stream of particles needs to be delivered to compaction rolls which compact it into a compacted strip which is then delivered to a sintering furnace, heated, and delivered to hot rolls or delivered relatively cold to cold rolls to produce a continuous strip of dense metal.
The particles in the stream of powder delivered to the compaction rolls need to be spread so that the stream of particles is substantially in the shape of a continuous strip of particles. Such a stream of particles is called herein a strip of particles. The loose particles are supported by the carrier.
Formerly the particles were delivered from a chute or carrier belt into the nip of the compaction rolls. When they were delivered from a chute, a single screed bar controlled the thickness of the particles spread onto the carrier or the lower roll of the compaction rolls.
During the hot rolling step, or even during the compacting step, cracks frequently occurred in the edges of the strip. One cause of the cracks was improper distribution of powder across the width of the compacting rolls. During reduction of thickness of the strip, for example by hot rolling, the strip elongated and the thickness was reduced. When one region of the strip had less mass than another, the region of lower mass could not elongate as much as the region of higher mass, and tensile stresses were produced in the lower mass region producing cracks.
A typical feeder for delivering metal particles into the nip of the compaction rolls controls the rate of powder feed by adjusting a round metering bar. The metering bar has a slot in it which is cut out in such a way that turning the bar opens or closes the slot allowing more or less powder to flow into the roll nip.